Electric switch



Oct. 12, 1948. s. E. HEYMANN ETAL ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed June 16, 1945 maur/C e man ,M Z WM W M Z 0 6 w l Oct. 12., 1948. s. E. HEYMANN Erm. 2,450,961

ELECTRIC SWITCH 2 Sheets-Sheet 2 Filed June 16, 1945 vvvmmv I f1 s J l, o, W W |.u w.- k f 1 w M .m ww j,

Patented Oct. 12, `1948 ELECTRIC SWITCH Seymour E. Heymann, Evanston, John H. Leslie,

Il, Winnetka. and William A. Marshall, Jr., Chicago, Ill., assignors to Stewart-Warner Corporation, Chicago, Ill., a corporation of Virginia y Application June 16, 1'945, Serial No. 599,816 16 Claims. (Cl. 200--81.4)

This invention relates to .electric switches and it has a wide range of application in the control of electric circuits employed for various pur-V poses. Particularly on airplanes or other vehicles in which there is considerable vibration it is important to provide a switch having its contact elements held either in or out of contacting position positively or with suiiicient deniteness so that vibration of the structure on which the switch is mounted shall not disturb the condition oi! the switch. Otherwise the device controlled by the switch may operate intermittently instead of continuously as intended or may be placed in operation at times when it should be de-energized.

One object of this invention is to provide a new and improved pressure actuated electric switch having means to prevent unintended operation thereof in response to vibration.

Another object of the invention is to provide a new and improved pressure actuated electric switch having a confined hydraulic iluid serving as a cushioning medium to prevent abnormal operation of the switch.y

A further object of the inventon is to provide a new and improved electric switch having hydraulic cushioningmeans for its movable parts and in which the cushioning means will be effectiveindependently of the position in which the switch is mounted. or carried.

It is also an object of the invention to provide a new and improved electric switch in which the contact making and breaking means operates within a `sealed chamber.

An additional object of the invention is to provide a new and improved means for actuating the contact making and breaking elements mechanically but by remote control as for example through the medium of a conned fluid.

`Other objects and advantages will appear from the following description taken in connection with the drawings, in which:

Fig. 1 is an axial sectional view showing the internal construction of a pressure` actuated switch embodying this invention;

Fig. 2 is an axial sectional view showing a modiiled construction,y taken at line 2-2 on Fig. 3:

Fig. 3 is a plan section taken substantially as indicated at line 3-3 on Fig. 2;

Fig. 4 is a detail section taken as indicated at line 4--4 on Fig. 23

Fig. 5 is a detail section taken as indicated at line 5-5 on Fig. 2;

electric switvh having Fig. 6 is a detail section taken as indicated at line 8-6 on Fig. 2.

As shown in Fig. l, the switch mechanism is enclosed in a housing comprising an end wall IIll and an end wall I2 with interposed filler memr bers` I4 and I6 which engage the peripheral portions of the end walls and are secured between them by clamping bolts or screws I8. The end walls IU and I2 will usually be oi cast metal construction although for some purposes synthetic plastics might be employed for these parts. The. iillers I4 and I6 are preferably of electrical insulating material because there is secured between them a partiton member 20 which is preferably of electrically conductive material and which has a lug 22 extending outside the casing and beyond the peripheral outlines of the illlers I4 and I6 for-attachment of a circuit lead wire 24 by means of-a binding screw 26. A pair of flexible diaphragms 28 and 3U extend across the charrber formed between the end walls I0 and I2,

the peripheral portions of the dlaphragms'being clamped between the fillers I4. I6 and the end walls I0 and I2 by the clamping action of the bolts I8. The diaphragms are spaced apart from each other and the end walls I6 and I2 are formed to provide spaces faces of the diaphragms and the respective end walls.

The wall I0 includes a centrally disposed recess or pocket 36 which houses a light spring 36 engaging the central portion ofthe diaphragm 28 for stabilizing it; and the wall I2 is formed with a centrally disposed recess or pocket 40 which encloses a somewhat heavier spring 42 reacting between the diaphragm 30 and a plate or disc 44 carried by an adjusting screw 46 having threaded engagement with the end wall of the pocket 46 with a lock nut 48 for retaining the screw in adjusted position. Each diaphragm is secured between reinforcing plates 50 and 52; and both diaphragms carry centrally disposed insulating washers 54 for seating the springs 38 and 42 respectively. At the center of each diaphragm a bolt 56 secures the .plates 5U washer 54 in assembled relation.

The bolt 56 in the diaphragm 28 carries an electrical contact button 58 and the bolt 56 in the diaphragm 30 carries a contact button 60 while the partition 20 supports a double-faced contact button 62 adapted to engage either the contact 58 or the contact 60. v'l'he contact 58 is connected toa lead wire 64 secured to a binding post 66, the

. connection being conveniently completed through a exible conducting wire 66 extending from the 32 vand 34 between the outer and 52 and the tition in this position of binding post 88 to the reinforcing plate 80 which is in contact with the bolt 56 at the center of the diaphragm 28. The contact l-80 is similarly connected to a lead wire 10 through a binding post '|2 and ilexible conductor '|4 extending inside the housing from the binding post 12 to the plate 50 associated with diaphragm 30. The binding posts 88 and 'I2 are secured in insulating bushings 'I6 which are set in suitable bosses formed in the end walls and |2 respectively.

As indicated in the drawing the space between the diabhragms 28 and. 30 contains a fluid medium 18 which is of the general character of the hydraulic uid employed in brake systems and the like'for transmitting movement and -this fluid completely fills the space between the diaphragms and is coniined by them. A small pori 80 in the partition 20`ail'ords restricted communication through the partition.

In the particular switch illustrated in Fig. 1 the spring 42 normally holds the contact 80 in engagement with the contact 82 on the partition 20, the diaphragm 30 being flexed toward the parthe parts, while the contacts 62 and 58 are shown separated. The space 82 between the diaphragm 28 and the end wail I0 is connected by a pipe or tube 82 with a source of pressure which may be gas or air pressure involved in the operation of an apparatus, as, for example, an internal combustion heater in which it is desirable that the igniter circuit shall not be closed until an air supply at a certain pressure is available for combustion or for circulation. or both. On the other hand, the air or gas supplied under pressure through the pipe 82 may be simply an operating medium for transmitting movement from a manual control device or other mechanism to the diaphragm 28. When a predetermined pressure is applied to the chamber 32 by the iiuid medium acting through the pipe 82, the diaphragm 28 will be moved toward the partition 20. This will gradually force the iluid '|8 through the restricted orifice 80, thus increasing the volume of iluid on the other side of the partition and forcing the diaphragm 80 away from the partition so as to separate the contacts 80 and 82, opening a circuit which includes the lead wires 24 and '|0. Continued pressure on the diaphragm 28 willbring the contact 58 into engagement with contact 82, thus closing the circuit which includes the lead wires 24 and 84.

In some instances there may be only one circuit involved and the lead wire may be omitted so that no particular result follows the separation of contacts 60 andk 82, but for other purposes it may be desirable to control two circuits or electrical devices in the manner described. In some cases the tube 84 between the diaphragm 30 and the end wall |2 will be merely a vent to provide atmospheric pressure for the space 84; in other cases the control of the electrical circuits connected with the switch device may depend upon a. differential, as between variable pressures applied respectively to the two diaphragm-is through the pipes 82 and 84. In either case, when the pressure through the pipe 82 is no longer suiiicient to overcome the pressure applied through pipe 84 plus the force of the spring 42, the iiuid 18 will be returned through the orifice 80 to the space between the partition 20 and the diaphragm 28, causing the contacts 58 and 82 to be separated and finally permitting the contact 80 to again engage contact 82.

In Figs. 2 to 5 inclusive there is shown a modiiled construction in which the leading from the chamber 34 contact elements 4 of the circuit making and breaking devices are located within the same enclosing housing as the diaphragms and retarding nuid but not within the body of the iluid itself. The housing is shown 5 at 80 as of cylindrical form and it encloses a spacer ring 82 secured in place by bolts 84 which extend through the marginal portion oi' the head or bottom wall 88 of the cylindrical casing and are threaded 'into a flanged ring 88 permanently l0 secured, as by welding. tothe cylindrical wall 80 of the housing. The bolts 84 thus serve to hold en d wall 88 in place At the same time the ciamping action of the bolts 84 secures marginal portions of a partition wall |00 between the ring 82 and the part 88 and similarly secures the marginal portions oi' diaphragms |02 and |04 which are located respectively above and below the wall |00. A central orifice |08 ail'ords communication between the space above the partition |00, and the space below it enclosed within the two diaphragms, and the entire space between the diaphragms is filled with a fluid |08 which may be in the nature of the iluid employed in hydraulic brake systems.

The two diaphragms |02 coupled together by means of a threaded rod ||0 which engages a threaded button 2 clamped in a central opening in the diaphragm |02, and a button ||4 similarly clamped in the central opening of the diaphragm 04. Stii'iening discs H8 and 8 are secured respectively against the upper face of the diaphragm |02 and the lower face of the diaphragm |04 by the buttons 2 and I I4. 'I'he upper end o! the rod I0 is screwed into the hub |20 of a ilexible three-armed spider |22', having the outer ends of its arms secured by screws |24 to a supporting member |28 mounted in the housing and attached to the cylindrical wall 80 thereof. 'I'he spider |22 thus centers and .1C steadies the rod I0 throughout the vertical range of its movement which results from flexing of the diaphragms |02 and I 04.

Such movement of the diaphragms occurs in response to changes of pressure acting against them within the housing 80; an inlet pipe |28 tapped into the bottom wall 88 will connect the housing with a source of pressure which may be gas or air pressure involved in the operation of an apparatus. The upper portion of the housing 80 is provided with an opening in the top wall 81 which may be merely a vent to atmosphere or which may be connected by pipe |88 with a second source oi' pressure when the device is to be responsive to the differential between the two pres- Sures.

The vertical movement of the rod ||0, in response to variations of pressure acting against the diaphragms |82 and |04, may be utilized to actuate several electric switches or contact deo vices; as shown, the housing 90 encloses two such l devices, each comprising a movable contact arm |82 and a pair of xed contacts |84 and |88. The arms |82 are clamped to a block |88 of insulating material supported by a bracket arm |40 which 05 extends from the ring 88, and suitable conductor 25 and |84 are positively stiil'ened by marginal mitted to the armsr |02 for `causing them to engage either the contacts |84 or the lower contacts |36 i'or closing the circuits corresponding respectively to said contacts. 'I'he contacts |34 are provided with conductor wires |62 and |54 leading outside the housing 90 and the contacts |86 are shown with conductors |66 and |68 similarly extendingoutside the housing 80.

The member |26 which is anchored in the housing includes radial arms |21 extending inwardly to form a substantially rigid spider and a coil spring |62 is arranged to react between this spider and a nut |64 which is adjustable on the threaded rod/H0. Preferably, cupped washers |66 and |68 are interposed between the ends of the spring and the spider and nut respectively. Thus the spring may be adjusted to provide an initial biasing force operating downwardly against the diaphragms |02 and |04 in opposition to an actuating fluid pressure entering the housing through the pipe' |28 and operative against the diaphragm |04, and in this manner the device may be set to respond to a predetermined pressure in that direction. If there is also a variable pressure supplied through the pipe |30 the operation of the diaphragms and actuation of the switch arms |32 will depend upon the difference between the two pressures modiiied by the -force of the spring |62 in one direction. In any event. the movement of the diaphragms in either direction can occur only as rapidly as permitted by the transfer 0f ilid |08 through the orifice |06 and the dash pot effect thus produced will prevent movement of the rod ||0 and bar |48 in response to vibration or jarring of the structure upon which the switch device is carried.

As shown in Figs. 2 and 4, the contacts |36 are denitely located by of insulating material |10 lwhich is bolted to a bracket |4I extending from the ring 98. To permit adjustment of the distance between the contacts |36 and |34, the latter are secured to a bar |12 of insulating material which rests upon spacer springs |14 disposed between the bar |12 and the bar |10. The securing bolts |16 which extend throughbothbars are provided with nuts |18 bearing against the upper face of the bar |12 so that adjustment of these nuts will compress the springs |14 to a greater or less degree and thus shift the bar |12 and the contacts |34 vertically with respect to the contacts |36. Corresponding adjustment of the range of movement of the diaphragms |02 and |04 is effected by means of a stop nut |80 on the threaded rod ||0 and a lock nut |82 associated therewith. The stop nut |80 positively limits upward movement of the diaphragms when it engages the washer |66 which abuts the under surface of the spider |26; downward movement of the diaphragms is checked when the button ||2 encounters a boss |84 upraised from the surface of the partition |00 adjacent the port |06 incidentally preventing closure of the port by the button ||2.

While there is shown and described herein certain structure embodying this invention, it is to be understood that the invention is not limited thereto or thereby but may assume numerous otherforms and that it includes all modifications, variations and equivalents coming within the scope of the claims.

We claim:

l. A pressure actuated switch device comprising a closed chamber, a pair of flexible diaphragms extending across said chamber in spaced relation mounting them on a bar aphragms respectively,

between them, a relatively rigid partition in the chamber disposed between said diaphragms and having a restricted orice permitting limited' flow of the iluid from one side of said partition t0 the other side, an electrical contact' element carried by each of said diaphragms and electrical contact means carried by the partition in position to engage the other contacts, means for applying pressure against one of' said diaphragms and yielding means reacting in the opposite direction against the other diaphragm.

2. A pressure actuated switch device comprising a closed chamber, a pair of flexible diaphragms extending across/said chamber in spaced relation with a quantity of iiuid coniined between them.

a relatively rigid partition in the chamber disposed between said diaphragms and having a restricted orice permitting limited flow oi' the uid from one side ofsaid partition to the other side. an electrical contact element carried by each of said diaphragms and electrical contact means carried by the partition in position to engage the other contacts, conduit means communicating with the chamber at one side of one di aphragm for applying iiuid pressure thereto. and yielding means reacting in the opposite direction against the other diaphragm.

3. A pressure actuated switch device comprising a chamber, a pair of exible diaphragms extending across said chamber in spaced relation to each other and in spaced relation to opposite walls of the chamber respectively, a relatively rigid partition dividing the space between the diaphragms and having a restricted orifice, a quantity of fluid filling the space between the diaphragms, separate pressure means in the spaces between the diaphragms and said opposite walls of the chamber operative against the dielectric contacts carried by said partition, and electrical contact elements carried by said diaphragms in positions to engage the first said contacts and movable into and out of their contacting positions by changes in the relative force of the respective pressure means.

4. A pressure actuated switch device comprising a hollow body composed of opposed end walls with fillers engaged between the peripheral portions of said end Awalls and forming the lateral walls of said body, clamping means securing said parts together with a relatively rigid partition dividing the space between said end walls and having its peripheral portion clamp between adjacent llers, a pair of exible diaphragms spaced from opposite sides of the partition respectively and peripherally supported by said nllers, a quantity of iiuid coniined between the diaphragms, said partition having a restricted orifice, electrical contact elements carried by said diaphragms, yielding means reacting between one of the diaphragms and the adjacent end wall, and means for applying fluid pressure between the other diaphragm and the adjacent end wall for shifting said contact elements.

v5. In a pressure actuated switch as defined in claim 4, said yielding means comprising a spring, and means accessible outside the body of the device for adjusting the tension of said spring.

6. In apressure actuated switch device as defined in claim 4, said iillers being of insulating material and the partition being of electrically conductive material with means for connecting a lead wire thereto outside the body of the device,

with a quantity of fluid confined whereby said partition cooperates with the con-` tact element of at least one of the diaphragms to complete an electric circuit.

7. A switch device comprising a pair of flexibie diaphragms forming opposite walls oi' a chamber with a quantity oi' substantially incompressible fluid confined between them, a relatively rigid partition extending across thechamber between said diaphragms and having a. restricted orifice, an electrical element carried on the inner face of each diaphragm and an electrical contact element carried by said partition in position to engage either of the other contacts and normally engaging one of them, and means arranged to apply pressure to the outer face of the diaphragm which carries the other contact.

8. A switch device comprising a pair of flexible diaphragms forming opposite walls of a chamber with a quantity of substantially incompressible iiuid confined between them, a relatively rigid partition extending across the chamber between said diaphragms and having a restricted orifice, an electrical contact element carried on the vinner face of each diaphragm and an electrical contact element carried by said partition ln position to engage either of the other contacts, supporting structure for said chamber, yielding means reacting between said structure and the outer face of one diaphragm normally holding its contact in engagement with the contact on the partition, and means arranged to apply pressure to the outer face of the diaphragm.

9. A pressure actuated switch device comprising a sealed chamber with a, pair of flexible diaphragms forming opposite walls of said chamber, a relatively rigid partition spaced between said diaphragms with a quantity of fluid filling the spaces between said partition and both diaphragms. said partition having a restricted orifice to permit limited flow of the fiuid from one side of the partition to the other side, a support for said chamber. means for applying pressure against one of said diaphragms, yielding means reacting against the support and opposing said pressure, electrical contact means carried by said support, and means connecting one of said diaphragms to said contact means to produce actuation of said contact means upon a predetermined movrment of said diaphragms. A

v10. A pressure actuated switch device comprising a sealed chamber with a pair of iiexible diaphragms forming opposite walls of said chamber. a relatively rigid partition spaced between raid diaphragms with a quantity of fiuid filling the spaces between said partition and both diaphragms, said partition lhaving a, restricted orlce to permit limited fiow of the iiuid from one side of the partition to the other side, a support for said chamber, switch meanslinciuding a fixed contact element and a movable contact element both mounted on the support, means for applying pressure against one of said diaphragms. yielding means reacting against the support and conos-ira fai/l pressure, and means connecting one of said diaphragms to said movable contact member for actuating it.

l1. A pressure actuated switch device comprising a sealed chamber with a pair of flexible diaphragms forming opposite walls of said chamber. a relatively rigid partition spaced between said diaphragms with a quantity of fluid filling the spaces between said partition and both diaphragms. said partition having a restricted orifice to permit limited flow of the fluid from one side of the partition to the other side, a support for said chamber, switch means including a fixed 8 a movable contact element both mounted on the support, means for applying pressure against one of said diaphragms, yielding means reacting against the support and opposing said pressure, a rigid member connecting a movable portion of one diaphragm with a movable portion of the other diaphragm and also connecting said diaphragms to said movable contact member for actuating it.

12. In a pressure actuated switch device as contact element and defined in claim 9, adiustable stop means positively limiting the movement of said diaphragm in response to said pressure.

13. A pressure actuated switch device comprising a sealed chamber with a pair o! flexible diaphragms forming opposite walls of said chamber, a relatively rigid partition spacedVbetween said diaphragms with Aa quantity of fluid filling the spaces between said partition and both diaphragms, the partition having a restricted orifice to permit limited flow oi' the fiuid from one side of the partition to the other side, a support for said chamber, switch means including a pair of fixed contact elements spaced apart on the support and a movable contact element also mounted on the support for engagement alternatively with said fixed contacts, means for applying pressure against one of said diaphragms, yielding means reacting against the support and opposing said pressure, means connecting one of said diaphragms to said movable contact member for actuating it. and stop means positively limiting the movement oi' the diaphragm in either direction.

` 14. In a pressure actuated switch device as defined in claim 13, means for adjusting the spacing of said fixed contact elements from each other, and adjustable stop means positively limiting the .movement of said diaphragm in both directions.

15. A pressure actuated switch device comprising a closed chamber, a pair of flexible diaphragms extending across said chamber in spaced relation, a relatively rigidpartition in the chamber spaced between lsaid diaphragms with a quantity of fluid filling the space between said partition and both diaphragms, said partitions having a restricted orii'lce to permit limited ow of the fiuid from one side of the partition to the other side, said chamber including a substantially gas type compartment between its end wall and one of said diaphragms and a second gas type compartment between its opposite end wall and the other diaphragm, an opening in each end wall for applying fluid" pressure against said diaphragms respectively for moving them in accordance with the differential between thc respective pressures in said compartments, and electrical contact means housed in the chamber and cony nected to one of Cthe diaphragms for actuation thereby in response to changes in said pressure differential.

16. In a pressure actuated switch device as defined in claim 15, a threaded rod connecting the two diaphragms and extending therefrom into one ofA the compartments of the chamber, a rigid spider supported in said compartment with a clearance opening at its center through which said rod extends, a flexible spider having arms attached to the rigid spider and a central portion threaded on to said rod, an adjustable nut on said rod with a spring reacting between said nut and said rigid spider biasing the diaphragms in one direction, and a stop nut on said rod en- 9 10 :useable with the spider to limit movement o! the diaphrazms in the opposite direction; UNITED STATES PATENTS v SEYMOUR E. HE Number Name Date JOHN H. LESLIE, IL 2.112.059 Arthur Mar. 22, 1938 WILLIAM A. MARSHALL. Jl. 5 2,314,266 Beam Mar. 16, 1943 2.350.938 Sparrow June 18, 1944 REFERENCES crrnb The following references are of record in thol file of this patent: 

